Method of casting articles.



. 2 SHEETS-SHEET 1.

PATENTED JUNE 9, 1908.

D. J. MURNANE.

, METHOD 0T CASTING ARTICLES.

APPLICATION FILED 1320.24, 1906;

PATENTED .TUNE 9, T908 D. J. MURNANE.

METHOD 0F CASTING ARTICLES.

APPLICATION FILED DEG.24,1906.

2 SHEETS-SHEET 2.

DANIEL J. MURNANE, OF KIRKWOOD, MISSOURI.

' METHOD oF cascrnve ARTICLES.

No. $80,293. Specification of Letters Patent. Fatemted June 9, 1908.

Application led. December 24, 1906. Serial No. 349,294.

To all whom it may concern:

Be it known that l, DANIEL J. MURNANE, a citizen of the United States, residing at Kirkwood, Missouri, have invented a certain new enduseful Improvement in Methods of Casting Articles, oi" which the following is a lull, clear, and exact description, such as will enable others skilled in the art to which it apnertains to make and use the same, reference being had to the accom )anying drawings, forming part of this speci cation, in Which- Figure 1 is a cross sectional view through the vacuum chai'nber of the apparatus which l have herein shown for practicing my method; Fig. is a plan view of the apparatus; Fig. 3 is a cross sectional view through the annealing furnace; and Fig. 4 vis a detail perspective view of the finished sheet. I

'This invention relates broadly to a metlod ot casting articles from molten metals.

Une object of my invention is to provide a method by which I am enabled to produce cast arti lles or objects having surfaces that arc pc,... ,fly smooth and free from air bubbles. V l

l have herein described my method as being employed for casting sheets of glass but it' should be understood that the broad principle of my invention could also be utilized in. the manufacture or" cast steel articles.

In the manufacture of articles or objects 'formed by casting molten metals, the faces of the article are usually rou h and very often the articles are `filled wit air bubbles or blow-rieles which make them defective. These rough faces are caused by the air Whichgets between the molten metal and the surface onto which the metal is poured and the air bubbles or blow-holes are caused by the air which is trapped by the molten 'metal and thus "prevented 'from escaping so that it eX- pands and consequently produces bubbles.

'ln the manufacture of cast sheets of glass, after the sheets have been formed the faces thereof' so 'rough that it is necessary to grindY of? the faces and then polish them to produce a' transparent plate of glass having ierlectly smooth surfaces. These grinding and polishing1 operations add greatly to the cost of producing cast sheets of glass, commonly known as plate glass, due to the fact that about one-halof` the sheet is consumed lor ground oli as Well as necessitating the employment of special machinery and operatives for running the machines.

By my improved method I am able to pro- 'duce sheets of transparent glass having perfectly smooth faces, Without grinding and polishing the sheet after it has been cast or rolled, Vthereby greatly reducing the cost of manufacture. li`urtl-rermrn'e, my methodenparent glass of any desired thickness.

One other object of my method is to produce a sheet of cast glass in whieh both laces have a fire `finish. Y

Bron-illy stated, my method consists in casting an article from molten metal in. a sealed chamber or inelosed space 'from which Furthermore, my metlurd facilitates the flowing of the metal and enables me to pour it at 'a lower teulpcrature than when it is poured in the atmosphere 'which quickly chills .the metal,

I have herein illustratedone form of appa-- ratus which may be employed for practicing my method in the manufacture of cast sheets of glass, but l; w ish it to be understood that various other kinds of apparatus could be used for arrying out my metliod .vitlmut degarting from the spirit of my invention.

he apoaratus herein shown consists of a vacuum chamber, namely, an inclosed space which is sealed and has air mzhausted therefrom prior to the operation of casting the and means for suspeiuliugftihe sheet vof glass in ain approxunatoly vertical or upright pofaees thereof Wil be subjected to heat and thus`- receive what is commonly termed a fire finish. By the term Waouuin 11amber'17 l mean a specially constructed chenibcr or inelosed space which' of great enough dimensions to receive toe'rcasting table and so that it forms kthe mule-shop in -which ables me to produce 'linishcd sheets of trans-.

air has been exhausted previous to pouring the metal so that the metal is poured 1n a v that l obtain an article which has sn'iooth surfaces and which is free 'troni llow-holfrs.4

sition in the annealing furnace so Athat both .10o mass of molten glass, an annealing furnace,

the other members used iu forming' the sheet men inside: oitnes' ffl , on 'the outside'ol the shell c through stu ing boxes in tie -ble 5, and ladle or' the casting1 operation trikes place, andvrhee ever l. have used seid term l. Wish to be understood as meaning an inclosed space of great enough dimensions to receive the meinbers used in the casting; `operation and not a .small inclosed space such as :i hollow mold into which metal poured to form an article.

Referring to the drawings, A desionates the vacuum chnmher which is formed by e shell .1 provii'led with air-tight doors and Windows 2 and 3. is so constructed that it will withstand the ressure to which it is subjected when the air 1s exhausted therefrom. l. have not illus trated the details of construction. of this shell., however, as it is immaterial, so far as my broad idea is concerned., in what manner the shell is constructed, the term shell being used merely for t purpose of designating the member or members which form the sides and top of the vacuum chamber. Cornmunicating with the interior of the shell is a conduit l that :is adapted to he connected to :1 pum'yor exhausting air 'from the interior ol die shell. A. castingr table 5 having a polished surface arrenged inside of the vacuum chamber, and cooperating with said table is s member 6 having a polished. surface which forms the mass of molten glass into a sheet, the table being providedalong its side edges with tengs which determine the thickness of the sheet. The member 6, as herein shown, is of segljnentul shape and is' adapted to be rocked over the teble 5, seid member and table being provided with cooperating rack teeth whic prevent said member' from slipping. roller or any other suitable device, however, could be used in place of the memher 6.

The table 5 is pref v,rebly :nocnted on al eerriage 7 which trevelsfon trucks S, and said table is pivotslly mounted between supports 9 on the carriage for a nurnose hereinafter described. The mass of citen glass is carried into the vacuum chamber A in e pot or ladle l() supported by carriage l1 which travels on an overhead track 1.2seid track comprising a movable portion l2 arranged which can he swung into an inoperative position, shown 1n Fig. 2, to permit the door 2in the shell to be closed and sealed efterthe pot of molten glass has entered the interior of the shell.

The various members which ere usedv in casting the sheet, namely, the member telpot lo, can'be operated fromv the outside of the shell l. bv suitable devices connected' thereto and extending shell, but prevted by Worknll dressed in eintight suits sind helmets te ,c .hairis supplied. by tubes extending from s source of air supply outside of the shelhsuch, ihr ennemie, as the suits used by divers. A

ier to have 'these members op This shell is airtight and scones ln carrying out my method, a pot oi molten glass is carried on the track lf! into the interior ol' the shell l and the doors und Windows of said shell are then securely sealed so that no air can penetrate into the shell l. Air is then exhausted from the shell through the conduit 4 so that a parti-el vacuun'i or as perfect a vacuum as practica-lne is created `inside of the shell 1. The pot l() then dumped to discharge the mass ot molten glass 13 onto the casting table end after said pot is moved out ofthe Way, the inember 6 is actuated to forni said mass into s sheet. 'Air is then admitted to the Vacuum chamber and' the door in one end of the shell is then opened and the carriage 7,' on which the table 5 is mounted, `is drawn out of the shell 1 or vacuum chamber, the tracks 8 in-A side of the vacuum churnher alining with tracks arranged outside of said chamber, the O outside tracks cornprismey Inova-ble po tions 8 which can be swungr into an inoperative position, as shown in F "E,` to permit the end door of the shell to he securely' sealed.

Preferably, a piece of" Wire mesh or rod le provided with an eye i5 is embedded in one edge of the sheet of glass during the opere- -tion of forming s" to enable the sheet to be gripped by thel member which supports it in s vertical position. in the annealing furnace B Which is srranged ndiztcent to the vacuum chamber, as shown in iig As previously stated, the casting?l trible is pivotally mounted. The object in construct ing the tahle iu this 'mf nel' is to ene-ble it to be tilted .into an approximately vertical posi tion efter it has been moved out of the via-cuum chamber so that the sheet ol glsss 'an he drawn or seine in e verticel position end thus not mer the surface of the glass which is in s.

semi-plastic 'condition after the casting opei-, ation has been completed and accordingly has to be removed therefronnwhile in this state. While l prefer to remove the sheet from. the table after the table has been moved l out of the vscuum chamber it may prove praptlcable to remove the sheet from the\ tahle'while the table is still 1n. the vacuum chamber end therefore do not wish it to he the sheet from the cestino table and'holdinv it suspended in a vertical position in the annealing furnace, consists of an erin i6 proA vided at its outer end with e hook which enA gages the eye i5 on the 'piece of mesh or other obj-ect that is embedded in the edge of the sheet.' This erm is connected to e sleeve. i? that er1-circles e hollow' standard 18 on a, carn -risge' 19 which'travels on elevated trucks 2G extending parallel to :the tracks 8 end else along the ontsideotne annealing furnace.

, tween the molten metal and the smooth and -faces of the sheet, due to the 'act that the ceases Said carriage is provided with a Winding-i shaft 21, and a chain or cable 22 is connected l to said shaft and to the sleeve 17 to which the arm is secured so that said sleeve can he l elevated and thus draw the sheet from the casting table. After the arm 16 has removed the sheet from the casting table said table is moved out of the Way and the arm is returned. to its normal position. The carriage is then moved alongside of the annealing,l furnace, the side wall of which is provided with an opening,` 23 so that the arm can project into the interior of the furnace, as shown in Fig. 3, and as the sheet is suspended in an upright or vertical position While it is in the annealing furnace both of its faces Will he suh jectcd to heat and thus receive a fire finish.

From the foregoing description it will he seen that my method enables me to produce a l'ast sheet of transparent glass of any desired thickness and having perfectly smooth faces without grinding uff and olishing:T the sheet is cast in a partial vacuum .so that air bubbles cannot form in the glass or get hem polished surfaces with which it comes in contact to cause the faces of the sheet to he rough. Furthermore, my method enables rnc to produce a cast sheet of glass in Which lboth faces have fire nish due to the fact that the sheet is suspended in a vertical position in the annealing furnace so that both of its faces are subjected to heat at the same time.

Having thus described my invention, what l claim as new and desire to secure by Letters Patent is: c

The method of making cast sheets of glass which consists in conveying a mass of molten into an air-tight chamber, exhausting air from said chamber to create a vacuum or partial vacuum therein, dumping said mass of molten glass onto a casting table and thereafter spreading said mass over said table and subjecting it `to pressure to forni a sheet; substantially as described,

ln testimony whereof I hereunto atlix'ny signature in .the presence of two Witnesses, this twenty-second day of December 1906. DANIEL li MURNANE. Witnesses WELLS L. CHURCH,

GEORGE BAKEWELL. 

